In this study, we will determine if airway inflammation resulting from 2 hour exposure to 0.25 ppm ozone with moderate exercise for two hours correlates with either mase cell numbers in the airway mucosa or mast cell mediators which as tryptase or TNF-alpha. This question is based on animal data which indicates the mast cell deficient mice have blunted inflammatory responses to ozone which are normalized with bone marrow transplantation.